Subdivision Surface Modifier partly closes holes
Subdivision Surface will virtually move your edges and create intermediate ones in order to smooth the whole shape. The part you show is only made of one big face with a hole in its center. In its try to smooth it, some vertices will be created in the hole area, which will give bad result. Here is what it gives with a simplified version (without and with the modifier):

If you cut your face the thing won't happen any more:

In your case you could fix it with this kind of topology: